Polychromators Specifications

The Model GAPB 1064-4-1K polychromator has been optimized for Thomson scattering measurements with Nd:YAG lasers. It can be easily modified for other lasers and/or other applications using different interference filters and detectors.

Mechanical Specifications

Overall dimensions: 8 cm x 25 cm x 75 cm

Weight: approximately 3.5 kg

Spectral channels: 4 (space for 4 more)

Temperature stability: water cooled

Iinput fiber adjustment: ± 1.6 mm in x, y, z

Detector adjustment: ± 1.4 mm in x, y, z

Detector monitoring: filter bypass*

Optical Specifications

Input fiber diameter: 2.8 mm nominal

Numerical aperture: 0.28

Incident angle of light: 4o at filter

Full cone angle of light: 4o at filter

Image size at detector: 2.0 mm nominal

Optics: BK7, broadband AR coated

Interference Filters

Diameter: 32 mm

Clear aperture: 27 mm

Peak transmission: 60 - 80% (typical)

Transmission@1064.3 nm: <10-5 (except laser filter)

Transmission out of band: < 10-4 @ 0.2 - 1.2 µ

Reflection out of band: >95% @ 0.6 - 1.07 µ

APDs

Detector: EGG C30956E

Diameter: 3.0 mm

HV bias: 250 - 400 V (typical)

Avalanche gain: 50 - 100 (typical)

Quantum eff. @ 1060 nm: approximately 40%

Quantum eff. @ 900 nm: approximately 80%

Noise enhancement factor: 3 (typical)

Amplifier

Input power: ± 8 V @ 45 - 100 mA

APD load resistor: 1 kohm

Output connector: 7 pin coax

Pulsed Channel

Background Channel

Gain: 40

Variable gain: 4, 8, 20, 40

Frequency response: 5 to 25 MHz

Frequency response: DC to 15 MHz

Output impedance: 50 ohms

Output impedance: 50 ohms

Noise @ 75 ns gate: 80 photoelectrons

Gain selection: TTL inputs

* For performance monitoring, each detector has an SMA fiber optic connector and lens so that light may be introduced via a fiber optic, bypassing the interference filter.